Default Windows 8 pc detects adb but not fastboot

I've had the same Rom for a while and I decided I want a new one. I remembered how to do everything from last time so I went and tried flashing the pacman rom. That worked but I unable to flash the boot.img because everytime I am in fastboot usb my computer doesn't see my device. .When ever I am in recovery or just on the phone normally my computer actually reconizes my phone. Some things to note are when I'm in fastboot it says waiting for device,I'm using a different computer then when I first rooted my device, fastboot off, usb debugging on
I could really use some help.
Thanks in advance!